Spilled oil in the coastal zone may be remediated through biodegradation by naturally occurring bacteria. It is possible to enhance the removal rates through addition of nutrients and biosolvents. These rates may differ within the intertidal area due to many environmental factors including surf washing. Laboratory experimentation is complex when there are so many factors involved. In a simple three factor remediation experiment, the effect of the timing of addition of a biosolvent, the type of nutrients added and the quantity of biosolvent relative to the amount of oil spilled were examined at three levels. A response surface methodology (RSM) was used to identify the key experiments to conduct and 17 separate trials were carried out with high, mid and low tide microcosms. The petroleum hydrocarbons were quantified by GC-MS methods and the data were examined with Design of Experiments (MODDE) and Partial Least Squares (PLS) Statistical (SIMCA-P) software. Different factors were important at the different intertidal locations: at low tide, the timing of application was most important while in the mid tide location, the proportion of biosolvent was most important. Of the nutrient additions, inorganic nutrients alone were more effective than organic forms of nitrogen or mixtures of urea with inorganic nutrients. Overall, the amount of biosolvent was the least important of the three factors examined. The use of RSM significantly reduced the experimental effort needed to investigate the factors and their interactions. (C) 2012 Elsevier Ltd. All rights reserved.